1. Field of the Invention
This invention relates generally to automatically sealing component packages, including but not limited to, delicate electronic components.
2. Description of the Prior Art
American and foreign industry and manufacturing have emerged into an electronics' dominated era. All aspects of our personal and business lives are effected by the widespread use of electronic products and computers. It has been discovered that the effective lives of electronic components can be increased substantially if they are operated in water-free and oxygen-free atmospheres. For this reason, certain electronic components have been hermetically sealed in miniature housings or packages containing oxygen- and water-free gases in order to make them suitable for use in applications wherein maximum component reliability is essential. For example, many of the electrical components used in guidance systems for missiles and other types of aircraft are hermetically sealed in packages containing water-free and oxygen-free gases for this reason. In most cases, packages commonly referred to as "flat-pack" packages which commonly have heights up to 1/4 inch and sectional dimensions of between 1/4 inch and 6 inches are used for containing electronic components. These packages preferably have either round, square or rectangular configurations and have either exclusively metallic or partially metallic and partially ceramic constructions. Generally, the most common types of "flat-pack" packages consist of an open housing-like base portion having a bottom wall and one or more upstanding side walls, and a substantially flat top or lid which is sealed to the upper edges of the base portion side walls to hermetically seal the interior of the package. Exclusively metallic package constructions are sealed by welding the metallic lids thereof directly to the metallic walls of the base portions thereof, whereas ceramic "flat-pack" package constructions are sealed by welding the lids thereof which are normally of metallic construction to metallic upper peripheral frames which are provided on the upper edges of the walls of the otherwise ceramic base portions thereof. Flatpack packages and other ceramic base packages such as side brazed packages are sealed by melting a solder ring between the package lid and a metalized surface on the ceramic base. In either case, however, the sealing of component packages is affected by sealing lids to base portions along peripheral seams of the lids to hermetically encapsulate the interiors of the packages. In this regard, apparatus of the type disclosed in the U.S. Pat. No. 3,239,644 to M. M. Nyborg et al. has been used for performing seam welding operations of this type, although other types of apparatus have also been available for such applications.
U.S. Pat. No. 3,449,540 to Yanko discloses an automatic welding system in which the welding head moves in accordance with plotted coordinates. Numerically controlled and employing an analog X-Y plotter, Yanko is capable of effecting a weld at predetermined positions on a given workpiece.
U.S. Pat. No. 3,665,148 to Yasenchak is a six-axis manipulator operating on a digitally controlled differential gear unit for application in the installation of panels on bodies in the automotive industry. Likewise, of general interest is U.S. Pat. No. 4,577,089 to Olson which illustrates an automatic welding machine comprising a gun that is positioned on a workpiece through magnetic rollers which grip the surface thereof. The position of the workpiece rests on a support plate which may be adjusted by a roller assembly thereunder.
Another U.S. Pat. No. 3,392,256 to Bradham relates to an apparatus for assembling miniature semiconductor networks to an essentially flat printed circuit board. It includes a jig for holding a plurality of miniature electronic network components for connection to a circuit board. The jig comprises a grid having a plurality of openings that coordinate with vertically operating electrodes.
U.S. Pat. #3,083,291 to Soffa is a device for mounting and bonding wafers of semiconductors. This invention operates through a sliding assembly where the wafer is positioned by use of a vacuum needle and examined under a microscope.
Demand in the electronics industry of today is for higher capability in batch processing, optimized sealing mechanisms and minimization of operator procedures. It is noted in the prior art that the seam welding apparatus capability was for receiving a single unit for operation thereon. The invention presented in this application meets the criteria of modern industry.